Laser-arc hybrid welding process of galvanized steel sheets

Galvanized steel sheets with a lap joint were welded by a laser-arc hybrid process. The hybrid system consisted of 2kW LD or YAG laser oscillator and frequency-modulated DC Pulsed MAG welding machine. In this experiment, the arc traveled on the specimens, following the laser beam with the interval of 2 mm. The results showed that the hybrid process had some advantages, such as deep penetration depth, high welding speed and high gap-tolerance, in comparison with the conventional MAG welding. Observations from a high-speed digital video-camera suggested that the zinc and iron vapors induced by laser beam irradiation stabilized the arc plasma. Effects of the incidence angle between a welding head and a specimen on the weld bead formations were also discussed. As a result, the welding speed of 2.0 m/min was achieved at 1.0 mm of gap length condition when the incidence angle was 50 degree.